Please tell me the major airlines' pet travel policies.  Note:  I have
a 55-pound husky, so this is not a little dog I can fit into a
carry-on.  Thanks very much.

Hi christmas:

Thanks for the interesting question. 

I found the following excellent page with links to all the major US
carriers' pet policies:

TRIPSwithPETS
URL: http://www.tripswithpets.com/petpolicies.asp

I've reviewed all the linked policies for you w.r.t. your large-ish
husky. I've pruned down the policies to the ones that I believe apply
to your situation *only*.

Large-ish Pets Allowed in Cabin: 
* none

Large-ish Pets Allowed as Cargo:
* American Airlines
* Continental
* Delta
* Midwest Airlines
* Northwest Airlines 
* United Airlines 
* US Airways

Special Care Options for Pets as Cargo:
* Continental - PetSafe program and Quickpak for speedier baggage recovery
* Midwest Airlines - Premier Pet Program 

Cost Per Pet:
* American Airlines - $100/pet
* Continental - depends on options chosen
* Delta - $75/pet
* Midwest Airlines - $75/pet
* Northwest Airlines - $80/pet
* United Airlines - $100/pet
* US Airways - $100/pet

Having review all the options, I'd have to say that Continental seems
to have the best service. (Of course, I'm not sure what it'll cost if
that is a concern.)

Bon Voyage to you and your best friend. :-)

Search Strategy (on Google): 
* "pet policies" airline

I hope this helps. 

websearcher

GREAT (and fast!) answer--both the answer and the link are very helpful.  Thanks!

I have used Continental (QuickPak) to send my dog unaccompanied two
times between CT and TX and can recommend them highly.

I've also used KLM for an international flight for my dog (Asia to
US), and they were great as well.

With this being the summer, be sure to ask each airline about their
temperature (weather) restrictions.  Some are more strict than others.

Best of luck to you!